Emergency mobile telephone

ABSTRACT

The cellular mobile telephone and system is provided wherein the cellular telephone automatically dials one or more prescribed emergency telephone numbers in the event of an emergency. Automatic dialing of an emergency telephone number is initiated by the user pressing a dedicated push button on the cellular telephone handset, or alternatively, upon the occurrence of an accident which is detected by the cellular telephone. After the cellular telephone dials the predetermined emergency number, the cellular telephone plays a recorded message which indicates that an emergency has occurred and that the telephone user is in distress. Alteratively, the cellular telephone user is allowed to participate in the emergency call upon receiving notification that the cellular telephone has successfully completed the automatic dialing and a connection has been established.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to mobile telephone systems, andmore particularly, to mobile telephone systems for us in an emergencysituation. Even more particularly, the present invention relates to acellular mobile telephone and system for automatically dialing anemergency telephone number and identifying the location of the emergencyso that the proper authorities are notified.

BACKGROUND OF THE INVENTION

Cellular mobile telephone systems are known in the art. Cellulartelephones for a given system operate within a predefined geographicregion which is divided into several small service zones referred to as"cells." Each cell includes one or more radio transmission stations, andthe transmission stations form a radio network which links the cellulartelephone transceiver with the local telephone network. As a result,cellular telephone users are able to make and receive telephone callsfrom anywhere within the geographic region.

Cellular telephones offer increased mobility and/or accessibility to theuser when making or receiving telephone calls as compared to thestandard telephone network. For example, most cellular telephones areinstalled in an automobile, truck, van, etc. The user is able to makeand to receive telephone calls, even while driving. Other cellulartelephones are designed to be portable so that the user may carry anduse the telephone wherever he or she travels. In any case, cellulartelephones permit a user to conduct a conversation over the telephonewithout necessarily having access to a conventional telephone.

Unfortunately, emergencies are known to occur, and cellular telephoneusers are not excepted from emergency situations. As an example, acellular telephone user driving in his or her vehicle may be involved inan accident. As another example, a cellular telephone user may sufferserious injury resulting from an accident caused by faulty equipment ata job site. Even further, a cellular telephone user might be assaulted,become seriously ill, or get lost in an unfamiliar area. In any of thesesituations, it is important that the cellular telephone user receiveemergency help quickly.

In the past, cellular telephones were useful only to a limited degree inthe event that the user was involved in some type of emergency. Ininstances where the cellular telephone user is fully alert and able todial the telephone, the cellular telephone user can simply dial anemergency number on the cellular telephone and request help. Theemergency number could be the number for the local police, theparamedics, 911, etc.

However, there are many situations which can arise where the cellulartelephone user is unable to dial such an emergency number using thecellular telephone. For example, if the user is involved in anautomobile accident, he or she may lose consciousness. Alternatively,the user may be disoriented and incoherent, and thus unable to make anemergency call. As yet another example, the cellular telephone usercould be assaulted and thus be prevented from using the telephone tocall for help.

Because cellular telephones in the past were not capable of dialing anemergency number automatically, in certain instances, emergency calls,especially repeat emergency calls, could not be made, and help could notbe provided. Moreover, previous cellular telephones were not capable ofdetecting the occurrence of an emergency, such as an automobileaccident, and such cellular telephones were not capable of automaticallydialing an emergency telephone number upon detecting such an emergency.Thus, cellular telephone users have been precluded in certain emergencysituations from receiving help that otherwise would have been availablehad an emergency number been dialed automatically by the cellulartelephone.

Additionally, even if the cellular telephone user were able to dial outand make a call in the event of an emergency, circumstances can arisewhere the user is unable to communicate with the person receiving thetelephone call. Oftentimes, the cellular telephone user may be unable toexplain that an emergency situation exists. For example, the user couldbe injured to the extent that he or she loses consciousness shortlyafter making the call. Alternatively, if the user is the victim of anassault, the user might be able to dial secretly; however, the user maynot be able to communicate openly after the call has been made. Unlesssome type of emergency message is conveyed automatically by the cellulartelephone, the receiving party would be unable to determine the purposeof the call or the identity or location of the caller.

Circumstances often arise where the location of the user is critical,but the user is not able to communicate his or her location in orderthat help may be provided. For example, the user could be lost in anunfamiliar area. Likewise, the user could be disoriented to the extentthat the user does not know his or her whereabouts. Although the usermay be able to dial the emergency number, the person or personsanswering the call would be unable to respond because the user'slocation is unknown.

Previous cellular telephones and cellular telephone systems couldidentify only the "cell" in which the user was located. Typically, sucha "cell" could cover a number of, and perhaps many, square miles. Itwould be extremely difficult for the authorities to conduct a blanketsearch of the entire area.

Accordingly, there is a strong need in the art for a cellular telephoneand system which enables an emergency number to be dialed automaticallywithout requiring that the user manually enter the number. Moreover,there is a strong need for a cellular telephone with which the user, bytouching a single dedicated key on the handset, can initiate the dialingof a predetermined emergency telephone number. Even further, there is astrong need for a cellular telephone which automatically dials anemergency number upon detecting that an accident has occurred. Inaddition, there is a strong need in the art for a cellular telephonewhich transmits a prerecorded emergency message after the emergencynumber has been dialed, thus notifying the receiving party that the useris in distress.

Moreover, there is a strong need in the art for a cellular telephone andsystem which can identify the location of a user in an emergency so thathelp can be provided. In addition, there is a need for a cellulartelephone system which can convey location information regarding thecellular telephone user to the appropriate authorities so that help canbe provided. Even further, there is a strong need for a cellulartelephone and system which can update the user location informationduring an emergency so that help can be provided even if the user isimmobilized or unconscious.

Accordingly, the present invention overcomes the aforementionedshortcomings of the known cellular telephones and systems and providesan improved cellular telephone and system for making and receivingemergency telephone calls. The present invention is summarized anddescribed in detail below.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a cellularmobile telephone and system wherein the cellular telephone automaticallydials one or more prescribed emergency telephone numbers in the event ofan emergency. Automatic dialing of an emergency telephone number isinitiated by the user pressing a dedicated pushbutton on the cellulartelephone handset, or alternatively, upon the occurrence of an accidentwhich is detected by the cellular telephone.

After the cellular telephone dials the predetermined emergency number,the cellular telephone plays a recorded message which indicates that anemergency has occurred and that the cellular telephone user is indistress. Alternatively, the cellular telephone user is allowed toparticipate in the emergency call upon receiving notification that thecellular telephone has successfully completed the automatic dialing anda connection has been established.

In another embodiment, after the cellular telephone has dialed theprescribed emergency telephone number, the cellular telephone begins toemit a radio location identification signal. The location identificationsignal, along with various direction finding techniques employed withinthe cellular system, enable the authorities to locate the user andrespond to the emergency call. During such time, the cellular telephonewill maintain the emergency call connection until the authorities haveresponded to the call, or until the user has chosen to terminate thecall.

According to one aspect of the present invention, an emergency cellulartelephone for use by a cellular telephone user in a cellular telephonesystem is provided, such telephone including receiving means forreceiving cellular radio communications within the system, transmittingmeans for transmitting cellular radio communications within the system,and automatic dialing means for dialing a prescribed emergency telephonenumber in response to a prescribed input.

According to another aspect of the invention, there is provided anemergency mobile cellular telephone system within which a cellulartelephone user having a cellular telephone can make and receivetelephone calls, such system including means for making and receivingcellular telephone calls using the cellular telephone, means foridentifying the location of the cellular telephone user, and outputmeans for communicating said location information.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrativeembodiments of the invention. These embodiments are indicative, however,of but a few of the various ways in which the principles of theinvention may be employed. Other objects, advantages and novel featuresof the invention will become apparent from the following detaileddescription of the invention when considered in conjunction with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings:

FIG. 1 is a schematic diagram of an emergency cellular mobile telephonesystem in accordance with the present invention;

FIG. 2 is a schematic diagram of a cellular telephone in accordance withthe present invention used in the system of FIG. 1;

FIG. 3A is a block diagram of the cellular telephone of FIG. 2 inaccordance with the present invention;

FIG. 3B is a flow chart showing the cellular telephone system logic forstoring an emergency telephone number in accordance with the presentinvention;

FIG. 3C is a flow chart showing the cellular telephone system logic forrecording and storing an emergency message in accordance with thepresent invention;

FIG. 4 is a flow chart showing the cellular telephone system logic forautomatically dialing an emergency telephone number in accordance withthe present invention;

FIG. 5 is a block diagram of the location identification section of thecellular mobile telephone system in accordance with the presentinvention;

FIGS. 6A and 6B are schematic diagrams showing two and three elementarrays which are used in connection with one embodiment of the locationidentification section of FIG. 5;

FIG. 7 is a schematic drawing of an alternate embodiment of an elementarray for use in the location identification section of FIG. 5;

FIG. 8 is a schematic drawing of an alternate mobile based embodiment ofthe location identification section of the cellular telephone system inaccordance with the present invention; and

FIG. 9 is a flow chart showing the system logic for the locationidentification section of the cellular mobile telephone in accordancewith the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the drawings, wherein like numerals are used to referto like elements throughout, an emergency cellular mobile telephonesystem 10 in accordance with the present invention is shown in FIG. 1.The cellular mobile telephone system 10 includes a cellular telephone 11(schematically shown) which typically, although not necessarily, isinstalled in an automobile 12, truck, boat, etc. Alternatively, thecellular telephone 11 is a portable device which is hand carded by theuser.

The cellular telephone system 10 of the present invention operates overa predefined geographic region 14. The geographic region 14 is dividedinto several small service zones referred to as "cells." As the cellulartelephone 11 user in automobile 12 moves about within the geographicregion 14 and through the cellular telephone system 10, the user remainsin radio contact with the local telephone network. Thus, as the usertravels about the region 14, the user can place a telephone call to thelocal telephone network without necessarily having access to a standardtelephone.

Each cell in the region 14 has one or more rf transmission stations 18which function to transmit and receive cellular information between thecellular telephone 11 user and the local telephone network. As isconventional, the user is always in radio contact with at least one ofthe rf transmission stations 18. Typically, the rf transmission station18 which is located nearest the cellular telephone 11 user is utilizedto maintain the radio contact with the cellular telephone. As the usermoves to another location, control of the radio link is handed off tothe next rf transmission station 18 along the way, as is known.

Each rf transmission station 18 in the cellular telephone system 10 isconnected to a central control station 20 for the system 10 by way of atrunk 24. At the central control station 20, the necessary switchingoperations are performed to hand off control of the cellularcommunications with the cellular telephone 11, as is known. The centralcontrol station 20 is connected into the local telephone network 26 bytrunk 28, thus providing the cellular telephone user with access to thelocal telephone network.

As is illustrated, the cellular telephone user in the automobile 12 maybe involved in an emergency which involves, for example, hitting tree29. In the event of such an emergency, the user becomes what is referredto herein as a "user in distress." The present invention provides acellular telephone which will automatically dial a preprogrammedemergency telephone number in case of such an emergency. The automaticdialing is initiated either by the user (if the user is conscious), orby the cellular telephone itself using some type of crash detector.After the connection has been completed, a prerecorded emergency messagerequesting assistance is communicated over the telephone line to theparty at the receiving end of the call. The cellular telephone alsoallows the user to interrupt the transmission of the prerecordedemergency message so that the user may provide his or her own message.

In addition, the cellular telephone system 10 and cellular telephone 11of the present invention engage in one or more of a variety of directionfinding techniques which permit the system 10 to identify the preciselocation of the user in distress. After the location is determined, thelocation information is automatically communicated to the receivingparty so that assistance may be dispatched promptly. If thepreprogrammed emergency number is the telephone number of the police orsheriff's department, information on the location of the user isreceived directly, and help can be provided. Alternatively, theemergency telephone number can be a dedicated telephone number withinthe system 10. A central dispatcher at the central control station 20receives the emergency call, records the relevant location information,and dispatches help by way of the appropriate authorities.

In one embodiment of the invention, the cellular telephone 11 causes theantenna 30 on the automobile 12 to emit a distress signal in the eventof an emergency. The distress signal is of sufficient power to bereceived by two or more of the surrounding rf transmission stations 18.Because the rf transmission stations 18 function as individual elementsin an antenna array, the central control station 20 applies knowndirection finding techniques, such as triangulation, to process thesignals received from the rf transmission stations 18 in order todetermine the precise location 31 of the user in distress. After thelocation is identified, the central control station 20 further processesthe distress and location information so that the proper (and preferablythe closest) authorities are notified and assistance is provided to theuser, e.g., in the location of the tree 29.

In an alternate embodiment of the present invention, the cellulartelephone 11 in the automobile 12 includes an on board locationidentification system. The location identification system employs anavigation system or the like to determine the location of the user indistress. After the cellular telephone determines the specific location,the telephone automatically dials the preprogrammed emergency telephonenumber and communicates the location information to the receiving party.An example of an on board location identification system which can beused in the present invention is a global positioning system such as theGPS System sold by Rockwell International. The global positioning systememploys a land-based unit in the cellular telephone which operates inconjunction with a satellite 35 to determine the exact locationcoordinates of the user in distress. The location coordinates are thentransmitted over the cellular telephone line to the party whoseemergency telephone number has been automatically dialed.

Referring now to FIG. 2, a cellular telephone 50 (designated 11 inFIG. 1) in accordance with the present invention is shown. The cellulartelephone 50 includes a handset 52 and transceiver 54. The handset andtransceiver are joined by an electrical 3O cable 56. As is common in theindustry, the handset 52 includes an earpiece 58 and microphone 60,shown in phantom in FIG. 2 as being on the opposite face of the handset52. The handset 52 further includes a display 60 and keypad 62.

To make a call under ordinary conditions, the cellular telephone userenters the number of the party to be called by pressing the appropriatesequence of digit and/or function keys on the keypad 62. The handset 52sends a series of control signals to the transceiver 54 and, as aresult, the transceiver 54 establishes a two-way cellular communicationlink with the appropriate rf transmission station 18 through antenna 30.

Incoming telephone calls to the cellular telephone 50 are received atthe antenna 30 and transceiver 54. The transceiver 54 decodes the radiosignal, and the audio signal is provided to the handset 52 usingconventional techniques.

In accordance with the preferred embodiment of the present invention,the cellular telephone 50 includes an emergency key 64 which, whendepressed, causes the cellular telephone to dial automatically anemergency telephone number which is preprogrammed and stored in memoryin the cellular telephone. Thus, when the cellular telephone user is indistress, the user can simply press a single key to initiate anemergency call. The preprogrammed telephone number could be that of thepolice, an emergency 911 service, an emergency service provided by thecellular telephone system 10, a family member, etc.

When the emergency call is dialed and connected through the transceiver54, a prerecorded message which is digitally or otherwise stored in thememory of the cellular telephone 50 is communicated over the cellulartelephone link to the receiving party. The user can interrupt theprerecorded message and provide his or her own message by pressing apredetermined interrupt code. Such a code can be a single function keyor a sequence of keys. The sequence may consist of one or more digitkeys and/or the "#" or "*" keys. Alternatively, the interrupt code canbe provided by a single dedicated interrupt key 65.

Moreover, while the emergency key 64 is described in the preferredembodiment as being a single dedicated key, it will be apparent to thosehaving ordinary skill in the art that the same function may be obtainedusing a unique sequence of depressed keys on the keypad. However, it isdesirable that the user be able to initiate the automatic dialing of theemergency telephone number without having to dial more than a fewdigits. Otherwise, the utility of the present invention is compromised.

In the event the cellular telephone is installed in an automobile 12 orother type of vehicle, the cellular telephone preferably includes acrash detector 66. The crash detector 66, upon detecting that anaccident has occurred, sends an electrical control signal along cable 68to the transceiver 54 instructing the cellular telephone 50 to dialautomatically the emergency telephone number as if the emergency key 64has been depressed. The crash detector 66 may include an impact sensor66d (shown in FIG. 3A) such as an accelerometer 66a (shown in FIG. 3A),a sonic sensor 66c (shown in FIG. 3A) designed to detect breaking glass,a mechanical sensor 66d (shown in FIG. 3A) on the front and/or rearbumper of the vehicle, motion detector 66b (shown in FIG. 3A) etc. Avariety of mechanisms for use as a crash detector 66 will be apparent tothose having ordinary skill in the art in view of the present disclosureand are within the intended scope of the present invention.

The transceiver 54, as is shown in FIG. 3A, includes a cellulartelephone control unit 70 which serves as the primary controller for thecircuitry in the cellular telephone 50. In addition, the transceiver 54includes an rf circuit 72 and the antenna 30 which combine to form theabove-described radio link between the cellular telephone 50 and therespective rf transmission station 18. The transceiver 54 also includesan audio and data signal processor 74 for performing the necessaryprocessing of the audio and digital signals between the control unit 70,rf circuit 72 and the handset 52. In addition, the transceiver 54includes memory 76 for storing data as well as the system program, alsoreferred to herein as the software program, for the control unit 70central processing unit.

The memory 76 also is used for storing the preprogrammed emergencytelephone number. The emergency telephone number can be that of thepolice, the sheriff's department, 911, a dedicated emergency servicenumber offered by the cellular telephone system 10, or the like. Asolid-state recorder 77 is used to record and to play back a digitizedemergency message. The message can be a brief explanation, such as, "Myname is Pamela, I am a cellular telephone user who is involved presentlyin an emergency. I am in need of assistance, please send help.Information as to my location will follow at the end of this message."

In the preferred embodiment, the control unit 70 is a microcontrollerwhich includes a central processing unit, an analog-to-digital (A/D)converter, a bi-directional I/O port and a pulse width modulationoutput. The central processing unit within the control unit 70 isprogrammable and may be programmed to perform all of the functionsdescribed herein, as will be apparent to those having ordinary skill. Anexample of a suitable control unit 70 is the commercially availableS80C552 8-bit microcontroller manufactured by the Signetics Corp.

The control unit 70 is connected to the rf circuit 72 by abi-directional serial data and control line 78. The rf circuit 72includes a receiver subsystem and transmitter subsystem (not shown), andthe signal on line 80 from the audio and data processor 74 serves tomodulate the transmitter subsystem. Line 81 connects the demodulatedaudio and control data signal from the rf circuit 72 receiver subsystemto the audio and data processor 74 which is coupled to the control unit70 by way of a bi-directional data and control line 84. An exemplaryaudio and data processor 74 which can be used in accordance with thepresent invention includes the commercially available UMA1000 dataprocessor manufactured and sold by the Signetics Corp. In addition,audio processors NE/SA5751 and NE/SA5750, also available from theSignetics Corp., are combined to form the audio and data processor 74.

The control unit 70 is coupled to the solid-state recorder 77 by way ofbi-directional serial data line 85 and control line 86. The solid-staterecorder 77 receives and digitally records an analog signal via line 87from the microphone 60. The outputs of the microphone 60 and thesolid-state recorder 77 are coupled to the audio and data processor 74by way of lines 88 and 89, respectively. Therefore, both conventionalaudio from the microphone 60 and a prerecorded audio message from thesolid-state recorder 77 can be selectively input by the controller unit70 to the audio and data processor 74. The audio is then provided alongthe modulation line 80. The prerecorded message from the solid-staterecorder is stored in memory 91 via line 92.

The commercially available MSM6388 solid-state recorder from Oki Data isused in the preferred embodiment, although it will be appreciated thatnumerous other recorders will function equally as well. Moreover,although the MSM6388 is preferred due to its reduced bandwidth, standardA/D and D/A converters built into the control unit 70 and the audio anddata processor 74 can be used as the solid-state recorder 77. However,it may be necessary to use a faster serial data bus or a parallel bus inorder to transmit a digitized voice message, as will be appreciated.

When the user wants to program a new emergency telephone number and/oremergency message into the cellular telephone 50, the user first setsthe control unit 70 in the program mode by pressing the appropriate keyson the keypad 62. The key can be a dedicated function key (not shown),or a predefined sequence of keys which the control unit 70 recognizes asan instruction to enter the program mode.

Referring now to FIG. 3B, a computer program flow chart representing thesystem logic for storing an emergency telephone number is shown. It willbe appreciated that an appropriate computer program or series of stepsor commands could be written by a person who has ordinary skill in theart, such as a computer programmer, to cause the circuitry and othercomponents of the cellular telephone 50 to carry out the stepsrepresented in the flow chart of FIG. 3B and in the other flow chartspresented herein. Such computer program is referred to herein as thesystem program of the software program which may be stored in memory 76,as is referred to above. Except as otherwise represented by the flowcharts and description provided herein, the system program operates in aconventional manner to carry out the normal functions provided byexisting cellular telephones.

Initially, the telephone is in a standby mode A which preferably isentered automatically when the telephone receives power. In step 95, theuser will request to record an emergency telephone number by pressing apredefined key sequence (or a dedicated key) on the cellular telephonekeypad. Upon receiving this request, the software program running on thecellular telephone's control unit 70 will determine if a valid digit 0-9has been pressed, as is illustrated in steps 96 and 97. If a "valid"digit is pressed, the control unit 70 will store the digit along withsubsequent "valid" key entries in the emergency telephone number storagearea in the system's non-volatile memory 76, as is shown in step 98.

If the user presses the terminate key (this can be, for example, the STOkey or any other predefined key sequence in step 99), the softwareprogram stops storing the telephone number, as is shown in step 100, andreturns to step 95 before the user request to enter the emergency numberis received.

If, in step 101, the user presses the abort key (that can be the CLR keyor any other predefined key sequence, for example), the control unit 70software program abandons storing the telephone number, as is shown instep 102, and returns to step 95 before the user request to enter theemergency number is received. If any other key is pressed, an errorcondition is indicated, as is illustrated in step .103, and the entry isignored. The error can be indicated via an audible, visible, or anaudible and visible signal from the handset display 60 and earpiece 58,for example.

FIG. 3C illustrates the system logic for recording an emergency messagein accordance with one embodiment of the present invention. Again, thetelephone is preferably in a standby mode A which occurs when power isapplied to the telephone. In step 105, the user will request to recordan emergency message by pressing a predefined key sequence (or adedicated key) on the cellular telephone keypad. Upon receiving thisrequest, the software program running on the cellular telephone controlunit 70 will enable recording, as is shown in step 106. In the preferredembodiment, the software program causes the control unit 70 to enablethe solid-state recorder 77 by way of the control line 86.

In step 107, the software program generates a tone on the earpiece 58 tosignal the user to start speaking into the microphone 60. This signalcan be an audible, visible, or an audible and visible signal.

During recording in step 108, the user speaks into the microphone 60,and the audio signal on line 87 is input into the solid-state recorder77, as is illustrated in FIG. 3A. The message is digitized and stored bythe recorder 77, and the software program monitors the memory usage. Ifa memory overflow condition occurs in step 109, the program terminatesrecording by causing the control unit 70 to disable the solid-staterecorder 77 in step 110. The program also notifies the user of the errorcondition by generating an error signal on the display, for example. Ifthe user presses a key on the keypad 62 during recording causing the"asynchronous event" shown in FIG. 3C, the software program isinterrupted. The asynchronous event causes the flow chart of FIG. 3C tobe entered at line 105a following to block or step 111. For example, thesoftware program responds to keys as follows:

A. If the terminate recording key is pressed in step 111 (this can be,for example, the END key used to terminate telephone connections, or itcan be any predefined key sequence), the software program terminatesrecording by turning off the solid-state recorder 77, as is shown instep 112, and updates the internal data structures to reflect that avalid emergency message exists in memory. The program then returns tothe original state in step 105.

B. If the abort recording key is pressed in step 113 (this can be theCLR key or any other predefined key combination), the software programterminates recording by turning off the solid-state recorder 77 andupdates the internal data structures in step 114 to reflect that a validemergency message does not exist in memory. The software program thenreturns to step 105.

C. If any other key or key sequence is pressed, the entry is ignored, asis illustrated in step 115, and the software program continuesrecording.

The software program for the control unit 70 provides that when a userin distress depresses the emergency key 64, a control signal on line 116causes the control unit 70 to access the emergency telephone numberwhich had been stored previously in memory 76. The control unit 70proceeds to retrieve the emergency number from memory 76 and goesthrough the same steps required to dial the telephone number as areotherwise taken when the user enters a telephone number and presses theSEND button to initiate a call.

A flow chart of the cellular telephone 50 system logic for automaticallydialing the emergency telephone number is shown in FIG. 4. Underordinary circumstances, the cellular telephone 50 exists in the standbymode of state A where the telephone is fully operational as a cellulartelephone for use in a conventional manner. As is shown in step 117, thecellular telephone control unit 70 constantly monitors its inputs todetermine whether a signal requesting that the emergency telephonenumber be automatically dialed has been received. Such signal can comefrom the emergency key 64 being depressed or, for example, from thecrash detector 66 upon the detection of a crash.

If a signal indicating an emergency dialing request is received, thecontrol unit 70 proceeds to step 118 where the cellular telephone 50implements the automatic dialing procedure. The emergency telephonenumber is retrieved from memory and dialed in the manner describedabove. After the call has been dialed, the control unit 70 determineswhether a connection was made, as is shown in step 119. If theconnection with the receiving party was made, the control unit 70 instep 120 causes the solid-state recorder 77 via control line 86 toretrieve the stored emergency message from memory 76 and to replay themessage continuously over the voice channel to the receiving party.

Specifically, the digitized emergency message is reconverted into ananalog signal using a D/A converter, preferably in the solid-staterecorder 77 or in the audio and data processor 74. The analog emergencymessage signal is provided to the audio and data processor 74 along line88 and is modulated onto the rf carrier through the rf circuit 72 by wayof line 80. The emergency message is thereby transmitted to thereceiving party so as to notify the party that the user is in distress.If, in step 119, the connection is not made, the control unit 70 of thecellular telephone 50 will return to step 118 and repeat the automaticdialing procedure.

While the cellular telephone 50 is in step 120, the user in distress hasthe option of interrupting the playing of the emergency message andinstead talking with the receiving party. If the user is conscious, heor she may be able to describe the emergency and/or to communicate hisor her location so that help can be provided. In order to interrupt theemergency message, the user simply depresses the appropriate key orsequence of keys on the handset 52 as described above. A sequencedetector programmed into the control unit 70 will detect the interruptsequence and allow the user to override the transmission of theemergency message by speaking into the microphone 60.

Alternatively, in step 121, the user may want to terminate the emergencydialing/message. The user simply depresses a dedicated function key orsequence of keys, resulting in an asynchronous event represented by line121a which causes the control unit 70 in the cellular telephone 50 toreturn to state A. In the event the connection is lost between thecellular telephone 50 and the receiving party, as represented by line122a, in step 122 the control unit 70 detects such an occurrence andreturns to state B in the system program.

In the preferred embodiment, the cellular telephone 50 emits a locationidentification signal in addition to a prerecorded message in the eventof an emergency. The location identification signal allows the cellulartelephone system 10 to employ direction finding techniques such astriangulation to locate the user in distress.

Accordingly, in step 118 the cellular telephone 50 will simultaneouslybegin to emit a location identification signal after detecting thesignal to dial the emergency number. The control unit 70 in the cellulartelephone 50 causes the rf circuit 72 to begin transmitting ahigh-frequency signal which can be detected by two or more antennas atthe surrounding rf transmission stations 18. Based on the relativeamplitude and/or phase of the location identification signal as it isreceived at the rf transmission stations 18, the cellular system 10 isable to determine the location of the user using a locationidentification as is described below.

As will be appreciated by those familiar with the art, the locationidentification signal preferably is transmitted from the cellulartelephone 50 at an increased power level as compared to ordinarycellular communications. The increased power level will result in thesignal reaching a greater number of rf transmission stations 18.Furthermore, the increased signal strength will provide even betterresolution in locating the user in distress based on reduced signaldegradation.

A block diagram of the cellular telephone location identification system123 is shown in FIG. 5. The location identification system 123 is partof the cellular telephone system 10, and antennas 18'a-18'c representthe respective antennas' elements at three of the surrounding rftransmission stations 18. Preferably, these three antennas 18'a-18'crepresent the antennas to which received signal strength of the locationidentification signal is greatest. Typically, this will be the antennaswhich are nearest the point where the user in distress is located.However, it is not necessary that the respective antennas be thenearest. It is only necessary that the antennas be properly positionedand receive a signal of sufficient strength to employ direction findingtechniques such as triangulation.

Each antenna element 18' functions as an element in an antenna arraywhich enables the system 123 to locate the user using one or more knowndirection finding techniques. While it is preferred that the system 123use three antennas in the array, it will be apparent that two or moreantennas will provide the necessary location information. Moreover, eachparticular antenna element 18' can consist of either a single antenna ora plurality of antennas in a sub-array as will be apparent to thoseskilled in the art. Furthermore, the antenna elements 18' can becomprised of the same antennas which are used at the rf transmissionstation 18 for ordinary cellular communications. Alternatively, theantenna elements 18' may be separate, dedicated antennas usedpredominantly in locating the user in distress. In addition, while thelocation system 123 is described as having the antenna elements 18'positioned at the same location as the rf transmission station 18, itwill be apparent that the antenna elements 18' and the antenna arrayformed therefrom can consist of antennas positioned in alternatelocations within the region 14.

When an emergency occurs and the cellular telephone 50 begins to emitthe location identification signal, the central control station 20receives the location identification signal from the antennas 18' alongtrunks 24. At the central control station 20, the respective signalreceived from each antenna is evaluated relative to the others in orderto determine the location of the user. The receiving system 124 measuresthe response of the various antennas 18' (also referred to below aselements or antenna elements) to the location identification signalemitted from the user in distress. The direction finding processor 125performs the necessary signal processing requirements to derive thelocation information from the output of the receiving system.Afterwards, the location information is sent to the output device. Thelocation information can consist of the coordinates of the user indistress so that help can be provided. The cellular region 14 issubdivided into a grid array, and the location coordinates pinpoint theexact location of the user in distress. The output device 126 routes thelocation information along the telephone network to the properauthorities or, more specifically, to the party whose number is theemergency telephone number programmed in the cellular telephone.

The location information received by the responding party can be in theform of the above-mentioned grid coordinates which are digitallycommunicated over the telephone line. Alternatively, a voice synthesizerwithin the output device 126 is utilized to provide a voice descriptionof the user's location based on such coordinates. In addition, thelocation coordinates can be further processed within the output device126 in order to provide street information, if available, regarding thelocation of the user. This is accomplished by a digitized map overlaywhich, in conjunction with the known coordinates, provides useful streetinformation. Many various approaches for conveying the locationinformation to the receiving party will be apparent in view of thepresent disclosure and are considered included in the invention.Accordingly, the scope of the present invention is not intended to belimited to the examples provided herein.

The specific technique of direction finding employed by the system 123can include one or more of several techniques known in the field ofdirection finding. A known technique commonly utilized in the defenseindustry involves what is referred to as triangulation. Basically, sucha system 123 employing triangulation techniques can be a scalar basedsystem in which the location of the user in distress is determined fromthe amplitude or phase response from the antenna elements 18'.Alternatively, the system can be a vector based system in which both theamplitude and phase of the signals received at the elements 18' areprocessed in the receiving system 124 and DF processor 125 to determinethe location of the user in distress.

Referring now to FIG. 6A, a two-element embodiment of atriangulation-type location identification system 123 is shown. Eachantenna element 18'a and 18'b is a single port antenna, and the antennaelements are electrically rotated within the direction finding processor125 so that the azimuth angles Θ_(A) and Θ_(B) can be determined basedon the amplitude and/or phase of the signal received from the respectiveelements. By using known principles of triangulation, the location ofthe user in distress may be determined.

An alternative to electrically rotating the respective elements 18'would be to use an element array 18' which actually encompassestwo-elements in close relation with one another. Therefore, the positionof the respective elements can be mechanically rotated and therespective azimuths Θ_(A) and Θ_(B) are determined. After Θ_(A) andΘ_(B) are determined, the direction finding processor calculates thelocation of the user in distress based on triangulation principles.

However, there can be some degree of ambiguity as to the location of theuser when using a two-element scalar system such as that shown in FIG.6A. As is know, an ambiguity can occur where location 130 appears to bean alternative location for the unit in distress. The circular lines 131drawn about the elements 18'a and 18'b represent the respective receivedsignal strength and/or phase of the location identification signal ateach element. The ambiguity results from the elements 18'a and 18'bbeing rotated electrically 180°. While several methods are possible forresolving the ambiguity in order to determine the exact location of theunit in distress, the preferred embodiment of the present inventionutilizes a three-element scalar system such as that which is shown inFIG. 6B.

The three-element embodiment avoids the 180° ambiguity found in thetwo-element system. In the three-element system, the three antennaelements are electrically rotated by the direction finding processor125, as described above. Again, the azimuth angles Θ_(A) and Θ_(B) aredetermined in the direction finding processor 125 and triangulationprinciples are applied to identify the location of the user in distress.The location is converted to grid coordinates and is provided throughthe output device 126 to the receiving party.

In a different embodiment of the location identification system 123, theantenna elements 18' are, in fact, a small antenna array with amultiport output. For example, shown in FIG. 7 is a single element 18'which includes a phased array of sub-elements 135. The azimuth andelevation of the unit in distress is determined by measuring the phasedifference of the signals at the output ports of the sub-elements 135using known techniques. The known azimuth and elevation angles describea vector 136 which points to the precise location of the user indistress. Again, the receiving system 124 and direction findingprocessor 125 perform such operation and provide the locationinformation to the output device as described above.

Still another suitable embodiment of the location identification system123 involves the element 18' of FIG. 7 being pivotably mounted to thetower 137. As a result, the element 18' can be moved in precise fashionin both the azimuth and elevation directions. Based on the amplitudeand/or phase of the response from each of the sub-elements 135, theantenna element 18' is able to determine the azimuth and elevationangles. Therefore, the location of the user in distress is againcalculated based on the vector 136. Such a pivotably mounted, multiportarray which is suitable for use in the present invention is commonlyused with a monopulse comparator system, as will be appreciated by thosehaving ordinary skill in the field of direction finding.

Any one or more of the above-described direction finding techniquesand/or antenna arrays can be used for determining the location of theuser in distress within the region 14. In addition, it will be apparentthat other variations are possible for use as part of the locationidentification system. Without going into an exhaustive recitation ofthe variety of direction finding techniques available, it should beappreciated that all are intended to be within the scope of the presentinvention as a part of an emergency mobile telephone system. Althoughsome direction finding techniques are more subject than others to directline-of-sight requirements between the cellular telephone antenna 30 andthe system 123 antennas, it will be appreciated that one or moredirection finding techniques will work in most environments. Therefore,although tall buildings, trees, etc may complicate processing in thedirection finding processor 125, they certainly will not preventidentifying the location of the user in distress.

One notable variation of the location system for the present inventionis shown in FIG. 8. In the above-described embodiments, the cellulartelephone 50 serves primarily in a passive role in the locationidentification system. The cellular telephone 50 simply emits a distresssignal which is then received and processed at the central controlstation 20 using the system 123. Alternatively, in the embodiment shownin FIG. 8 the cellular telephone 50 plays an active role in determiningthe location of the user in distress. In this particular embodiment, thecellular telephone 50 employs an internal navigation system, or portionthereof, which is capable of determining the location of the user indistress and communicating the information to the central controlstation 20. The central control station in turn relays the locationinformation to the receiving party.

Most preferably, the internal navigation system, or a portion thereof,is included in the cellular telephone 50 as a location identificationcircuit 140 (FIG. 3). When the signal for emergency dialing is receivedby the control unit 70 as described above, the control unit activatesthe location identification circuit 140. The location identificationcircuit 140 in combination with the control unit 70 receive positioninformation through the rf circuit 72 from one or more preestablishedreference sites which are located about the region 14. Based oninformation received from the reference site or sites, the locationidentification circuit 140 determines the location of the user indistress relative to the reference site. The location information iscommunicated to the control unit 70 by way of line 142 then encoded andtransmitted over the cellular link to the emergency number dialed. As aresult, the proper authorities are notified of the location of the userin distress, and help can be dispatched.

The location information transmitted from the cellular telephone 50preferably is in the form of location coordinates, for example longitudeand latitude, which correspond to those on a map of the region 14. Asdescribed above, these coordinates may be converted manually orelectronically in order to arrive at a more workable street address orthe like. The location information is encoded on the rf signalpreferably using a DTMF encoding scheme, although other encoding schemesare also applicable.

In a preferred embodiment, the location identification circuit 140establishes a link with a navigational satellite 35, as is shown in FIG.8. Using location principles commonly employed with surveying equipment,the cellular telephone 50 communicates with the satellite 35 in order todetermine the location of the user in distress. The cellular telephoneprocesses the information received from the satellite 35 to arrive atthe location coordinates, and the location information is thencommunicated by the cellular telephone 50 to the appropriate party.

In still another embodiment, the location identification circuit 140actively communicates with one or more rf transmission stations 18 whichserve as reference sites. The rf transmission stations 18 transmitlocation reference information which the cellular telephone 50 receivesand utilizes to determine the location of the user. The actual locationof the user is determined using techniques such as those employed inlong range navigation (LORAN) systems used in boating, or another typeof global positioning system such as Rockwell International's GPS. Basedon the signals received from the rf transmission stations 18 serving asbeacons, the location identification circuit determines the location ofthe user in distress and again the information is communicated to theappropriate party.

While the invention has been described above in the context of the userin distress remaining at a fixed location, there are situations whichcan arise where the user in distress changes location within the region14. For example, the cellular telephone user could be assaulted in hisor her own car and ordered to drive somewhere. As another example, auser having a portable cellular telephone could be kidnapped andmobilized without knowledge of his or her destination. Alternatively,the user involved in an accident or under medication may be sodisoriented that, although the user is able to activate the locationidentification system, he or she continues to travel about during suchtime as it takes for help to arrive.

In such situations, the location identification system 123 and/or thelocation identification circuit 140 of the cellular telephone 50operates to provide updated information regarding the location of theuser in distress. Using the location identification system 123 shown inFIG. 5 wherein the cellular telephone 50 functions mainly as a passiveemitter, the direction finding equipment (124, 125,126) at the centralcontrol station 20 continuously updates the reading on the location ofthe user. Whenever the location of the user in distress changes ascompared to the previous reading, preferably the new locationinformation is communicated to the proper authority as described above.

Alternatively, in an embodiment where the cellular telephone 50 activelydetermines the location of the user in distress such as in the systemdescribed with respect to FIG. 8, the location identification circuit140 provides the updated information to the proper authorities. In FIG.9, a system flow chart for the emergency message dialing procedureincluding location update provisions is shown.

Referring to FIG. 9, generally, the cellular telephone 50 is in state Awhich represents the standby mode. The control unit 70 of the cellulartelephone 50 then awaits the arrival of the signal (e.g., as a result ofthe crash detector 66, the depression of the emergency button 64, etc.)indicating that a request for emergency number dialing has been made, asis shown in step 150. When such signal is received, the control unit 70activates the location identification circuit 140 as is shown in step152 by way of control/data line 142. The location identification circuit140 then attempts to communicate through the rf circuit 72 with thesatellite 35, rf transmission station 18, or other reference site orsites so that the location identification circuit 140 is able todetermine the location of the user.

In step 154, the control unit 70 determines whether the location of theuser has in fact been identified, preferably by the setting of a flag.If not, control is returned to step 152 and the location identificationcircuit 140 again attempts to identify the user location. After thelocation has been identified, the control unit 70 implements theautomatic dialing of the emergency number stored in memory 76 asdescribed above and as is shown in step 156. After the connection isdetermined to have been made in step 158, the cellular telephone 50 instep 160 transmits the emergency message to the receiving party alongwith the location information determined in step 152. The receivingparty processes the location information and help can be dispatched.However, in the event the connection was not made in step 158, controlis returned to step 156 and the automatic dialing procedure isre-implemented.

After the location of the user in distress initially has beentransmitted to the receiving party in step 160, the locationidentification circuit periodically updates the location of the user asis shown in step 162. Control is returned to step 160 after each update,and the updated location information is transmitted to the receivingparty. In one embodiment, the updated location information istransmitted after each update. Alternatively, the control unit can byprogrammed to retransmit the updated location information only if thelocation of the user in distress has changed since the previousdetermination. This can be accomplished by storing the locationinformation in memory after each transmission and by comparing theupdated information with that of the previous update. If the locationchanges, transmission of the updated information will proceed as before.

As with the system flow chart shown in FIG. 4, if at any time during theemergency dialing procedure the user inputs an "end transmission" code,the cellular telephone 50 will terminate the connection and return tostate A. Moreover, if for some reason the connection is lost during theemergency dialing procedure, the cellular telephone will go to state B.From state B, the cellular telephone will proceed with steps 152-162 asbefore in activating the location identification circuit 140 and inimplementing the automatic dialing.

As a result, the cellular telephone 50 of the present invention operateswithin the system 10 to provide the automatic dialing of an emergencynumber and the playing of an emergency message. In addition, thecellular telephone 50 serves to determine and provide locationinformation concerning the location of the user in distress. Thelocation information can be provided to the receiving party regardlessof whether or not the user has lost consciousness. Help is thendispatched, where otherwise the user would not be able to verballycommunicate his or her location.

There are other scenarios in which the present invention would beuseful; only a few have been described herein. Although the inventionhas been shown and described with respect to certain preferredembodiments, it is obvious that equivalents and modifications will occurto others skilled in the art upon the reading and understanding of thespecification. The present invention includes all such equivalents andmodifications, and is limited only by the scope of the following claims.

I claim:
 1. A cellular telephone, comprising:a receiver for receivingcellular radio communications; a transmitter for transmitting cellularradio communications; a controller coupled to the receiver and to thetransmitter; an operator input device coupled to the controller, theoperator input device receiving operator inputs and providing operatorinput signals to the controller indicative of the operator inputs; anemergency input key coupled to the controller, the emergency input keyreceiving an operator emergency input and providing an emergency inputsignal to the controller indicative of the operator emergency input; acrash detector, coupled to the controller, sensing parameters indicativeof a crash and providing a crash signal to the controller indicative ofthe parameters sensed; a first memory coupled to the controller andstoring a pre-programmed telephone number corresponding to an emergencyresponder; a second memory coupled to the controller and storing apre-recorded emergency message including identification informationassociated with a user of the cellular telephone; a microphone coupledto the controller and providing voice signals to the controller inresponse to the user speaking into the microphone; wherein thecontroller is configured to detect a distress situation based on inputsfrom the emergency input key and the crash detector, and to access thefirst memory and initiate cellular communication using thepre-programmed telephone number and to access the second memory and playthe pre-recorded message repeatedly once cellular communication has beeninitiated and established with the emergency responder, and wherein thecontroller is further configured to stop playing the pre-recordedmessage and transmit voice information based on inputs from themicrophone and the operator input device.
 2. The cellular telephone ofclaim 1 wherein the crash detector comprises:an impact detector coupledto the controller and configured to be coupled to at least one of thefront and rear bumpers of a vehicle within which the cellular telephoneis located and to provide an impact signal to the controller in responseto sensing impact.
 3. The cellular telephone of claim 1 wherein thecrash detector comprises:a sonic detector coupled to the controller andconfigured to detect the sound of breaking glass and provide a crashsignal to the controller in response to detecting the sound of breakingglass.
 4. The cellular telephone of claim 1 wherein the crash detectorcomprises:an accelerometer, coupled to the controller, in providing thecontroller with a crash signal in response to the accelerometermeasuring physical characteristics indicative of a crash.
 5. Thecellular telephone of claim 1 wherein the crash detector comprises:amotion detector coupled to the controller and detecting motionindicative of a crash and providing a crash signal to the controller inresponse to detecting the motion indicative of a crash.
 6. Incombination, a cellular telephone and a base station the cellulartelephone comprising:a receiver for receiving cellular radiocommunications; a transmitter for transmitting cellular radiocommunications; a controller coupled to the receiver and to thetransmitter; an operator input device coupled to the controller, theoperator input device receiving operator inputs and providing operatorinput signals to the controller indicative of the operator inputs; anemergency input key coupled to the controller, the emergency input keyreceiving an operator emergency input and providing an emergency inputsignal to the controller indicative of the operator emergency input; acrash detector, coupled to the controller, sensing parameters indicativeof a crash and providing a crash signal to the controller indicative ofthe parameters sensed; a first memory storing a pre-programmed telephonenumber corresponding to an emergency responder; a second memory coupledto the controller and storing a pre-recorded emergency message includingidentification information associated with a user of the cellulartelephone; a microphone coupled to the controller and providing voicesignals to the controller; and wherein the controller is configured todetect a distress situation based on inputs from the emergency input keyand the crash detector, and to access the first memory and initiatecellular communication using the pre-programmed telephone number and toaccess the second memory and play the pre-recorded message repeatedlyonce cellular communication has been initiated and established with theemergency responder, and wherein the controller is further configured tostop playing the pre-recorded message and transmit voice informationbased on inputs from the microphone and the operator input device; andthe base station comprising:a location detector configured to locate thecellular telephone; and a notifier configured to notify a nearestemergency responder located geographically nearest the location of thecellular telephone.
 7. The combination of claim 6 wherein the controllerof the cellular telephone is further configured to generate a distresssignal in response to receiving the crash signal from the crashdetector, the controller transmitting the distress signal; andwhereinthe location detector of the base station is configured to locate thecellular telephone in response to the distress signal being transmittedfrom the cellular telephone.
 8. The combination of claim 7 wherein thedistress signal is more powerful than a typical cellular radiocommunication signal transmitted by the transmitter.
 9. The combinationof claim 6 wherein the notifier of the base station is configured toprovide the emergency responder with geographic information indicativeof the location of the cellular telephone.